The Basics: Connecting Sentences (Part 1)

Part 3 gave you the tools to modify nouns and end sentences with tense. But real Korean, whether spoken or written, rarely happens in single-clause sentences. Native speakers connect thoughts constantly, and they do it with specialized endings that attach to verbs. This post covers the connectors you’ll use to list actions, sequence events, and describe simultaneous activities. Instead of saying “I ate. I left.”, you can say: “I ate and left.”

-고: and (listing actions, not connecting cause)

-고 is your default “and” for verbs. Attach it to the verb stem to list actions in a neutral, unordered way. The tense is carried by the final verb, not by -고 itself.

• 밥을 먹고 커피를 마셨어요. = I ate rice and drank coffee.
• 학교에 가고 친구를 만나요. = I go to school and meet a friend.
• 책을 읽고 운동해요. = I read books and exercise.

The order in the sentence is the order they happened if that matters, but -고 itself doesn’t emphasize sequence. It just connects. For tight cause-and-effect or clear “do A then B” sequencing, you’ll want -아/어서 (next).

Negative listing with -지 않고

To say “do A and not do B,” attach -지 않고 to the verb you’re not doing, then state what you are doing afterward.

• 밥을 먹지 않고 커피만 마셨어요. = I didn’t eat rice and only drank coffee.
• 공부하지 않고 잤어요. = I didn’t study and slept (instead).

-아/어서: because, so, and then (sequential cause)

-아/어서 has two jobs, and both rely on a logical or temporal flow. Attach -아서 after stems ending in ㅏ/ㅗ, -어서 for everything else, -여서 for 하다 (which contracts to 해서).

Job 1: Reason or cause (“because”)

• 피곤해서 일찍 잤어요. = I was tired, so I slept early. / Because I was tired, I slept early.
• 비가 와서 집에 있었어요. = It rained, so I stayed home.

Job 2: Sequential actions (“and then”)

Unlike -고, -아/어서 implies that the second action happened after the first, and there’s a natural connection between them.

• 친구를 만나서 커피를 마셨어요. = I met a friend and (then) drank coffee.
• 신발을 신어서 나갔어요. = I put on shoes and went out.

The difference from -고 is subtle but real. -고 just lists; -아/어서 suggests the first action enabled or led to the second. It can also describe future/intended sequences.

-다가: switching mid-action

-다가 attaches to a verb stem and means “was doing A, then (interrupted) did B.” It emphasizes that the first action was in progress and got cut off or switched.

• 학교에 가다가 친구를 만났어요. = I was going to school and (then) ran into a friend.
• 책을 읽다가 잠들었어요. = I was reading and fell asleep (in the middle).
• 밥을 먹다가 전화를 받았어요. = I was eating and received a call.

The -다가 part can be dropped if the interruption isn’t important, but if you want to highlight that you were in the middle of something, -다가 is your marker.

A special case: you can also use -다가 with the same subject only. If the subject changes mid-sentence, you’d use -는데 or other connectives (covered in Part 5).

-고서: and then (with emphasis on completion)

-고서 is -고’s more emphatic cousin. It means “and then” with a strong sense that the first action was fully completed before the second started.

• 밥을 먹고서 나갔어요. = I ate and then went out (after finishing eating).
• 숙제를 하고서 TV를 봤어요. = I did homework and then watched TV.

In everyday speech, -고 is often used where -고서 technically fits. -고서 adds a shade of “finish this first, then do that.” It’s not required, but it’s useful when you need that extra clarity.

Simultaneous actions: -(으)면서 and -(으)며

These two are near-identical in meaning. Both mean “while doing A, (also) doing B.” Attach -으면서 after a consonant, -면서 after a vowel. For -(으)며, same rule: -으며 after a consonant, -며 after a vowel.

The distinction is register: -(으)면서 is more common in spoken Korean; -(으)며 leans slightly more formal or written. Functionally, they’re interchangeable.

Using -면서

• 음악을 들으면서 운동해요. = I exercise while listening to music.
• 커피를 마시면서 읽었어요. = I read while drinking coffee.
• 걸으면서 전화했어요. = I made a phone call while walking.

The action before -면서 is the background activity; the main verb after it is the foreground. But you can flip the order without changing the meaning.

Using -며

• 그는 웃으며 말했어요. = He said it while laughing.
• 학생들이 이야기하며 걸어갔어요. = The students walked while talking.

In formal writing, -며 is used for listing attributes as well.

Comparison chart: Which connector when?

All of these assume the same subject unless context clearly indicates otherwise. If you need different subjects, you’re entering the territory of -는데, -지만, and -니까, which Part 5 will cover.

Putting them together in a paragraph

See how they work in a single stretch of natural Korean:

아침에 일어나서 샤워를 했어요. 그리고 밥을 먹고서 학교에 갔어요. 버스를 기다리면서 음악을 들었어요. 학교에 가다가 친구를 만나서 같이 걸었어요.

I woke up in the morning and showered. Then I ate and went to school. While waiting for the bus, I listened to music. On the way to school, I ran into a friend, so we walked together.

Notice how -아/어서, -고서, -면서, and -다가 each pull their own weight. None of them translate directly to a single English word, but together they make the Korean flow feel more natural.

Also, in every day life, you’re more likely to use 학교에 가는 길에 친구를 만나서 than you are to use the 학교에 가다가 친구를 만나서 that was used in this sentence, altough both of them are perfectly understandable.

Why this matters for speaking naturally

Listen to any Korean conversation and you’ll hear these connectors every few seconds. They’re what turns a series of simple sentences into something that sounds like a real person talking, not a textbook exercise. The mistake most learners make is avoiding them by sticking to short, separate sentences because they’re safer. While it’s good to start with, the only way to sound natural is to start linking your thoughts the way Koreans actually do.

Know a lot of grammar but vocabulary is holding you back? Learning some simple Hanjas give you access to tens of words. While it won’t make you understand everything, you’ll improve and be able to guess new words’ meanings more often.

Part 5 will cover contrast and conditionals.